1. Field
The present invention relates to wireless data communication. More particularly, the present invention relates to a novel and improved method and apparatus for scheduling packet data transmissions in a wireless communication system.
2. Background
In a wireless communication system, a base station communicates with multiple mobile users. Wireless communications may include low delay data communications, such as voice or video transmissions, or high data rate communications, such as packetized data transmissions. U.S. patent application Ser. No. 08/963,386, entitled “METHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,” filed Nov. 3, 1997, now U.S. Pat. No. 6,574,211, issued on Jun. 3, 2003 to Padovani et al., describes high rate packet data transmissions, and hereby expressly incorporated by reference.
Packet data transmissions are not required to be low latency transmissions, and therefore allow the base station flexibility in scheduling mobile user transmissions within a system. Once scheduled, the base station may transmit data to as little as a single mobile user during a given time period. In general, scheduling of packet data mobile users in a system has two goals. The first goal is to optimize the utilization of each channel. The second goal is to allocate transmissions to mobile users fairly. The two goals sometimes compete. For example, channel quality conditions and the amount of pending data for a given user may result in excessive time allocations to that user particularly at the expense of other users.
There is a need, therefore, for a fair method for scheduling packet data transmissions to mobile users that is channel-sensitive.